Bell-ringing transformer.



Patented Mar. 26, 1912.

WTNESSE'S: ZAZVENTDR WQ( .5J/END Ef JHNNESEN y. im MM 'BM y i TTY 30formers of this character so that if vthe-sec- UNTTED STATES PATENTormon- SVEND E. JOHANNESEN, OF \PITTSFIELD,. MASSACHUSETTS, ASSIGNIOR TGENERAL ELECTRIC COMPANY, A CORPORATION OF NEW YORK.

BELL-itineraire TRANsrom/LER.

Specication of Letters Patent. V Patented Mar. 26, 1912.

Application sied August 14, 1909. serial No. 512,8'14.

y and useful Improvementsl in Bell-Ringing `value, andthe transformerswill be able to stand this short circuit for a long period ofTransformers, of which the following is a specification.

My invention relates to electrical insformers. A i

Although it is" not limited in its appli- `cation, it is moreparticularly adapted for use in connection with those transformers whichare employed for ringing electric bells.

One of'the chief requisites of bell ringing transformers is that theyshall be constructed as cheaply and at the same time asdurably aspossible, as they are used for the energization of electricalA circuitsof comparatively minor importance. In such circuits there is a greatpossibility of the bell, the wiring, or other devices in series with thesecondary of the transformer, being short circuited, which would cause alarge current to flow in the secondary winding, unless some precautionsare taken to prevent it. Because of the size of these transformers, itis hot convenient to connect the protective` device in series with them.It is therefore customary to design transondary winding .becomes shortCirc/suited, the short circuited current-will be limited in time. Inorder to reduce as far as possible the size, and, therefore, thecostofsuch transformers, the short circuited currentA must be made assmall as possible, as by so doing the size ofy wire used for bothprimary and secondary 'winding may be made aminimum, and'hence the costofthe transformers may be made a minimum. The object of my' inventionthen .is the construction of a transformer which will givea smallershort circuited currentthan is given by those transformers .at presentin use, and thusI effect a considerable saving in the cost of such-4transformers. In the past, ltransformers of this character with a largemagnetic leakage between/ the primary and secondary sh'ort circuitedcurrentA will be greatly 1n excess of the current'which is requiredunwinding is used,l

der normal operating conditions. .I have found that by a specialconstruction and arrangement of the transformenwindings, I

am enabled to reduce the short circuited current sothat it will not begreatly in eX- cess of the normal load current, and I am therefore ableto -decrease thesize of the wire used for the windings and thus decrease the' cost of a transformer without impairing its abil-itytostand ashortcircuit fora long peri0d.

For a further understandingof my inventilon, reference Vmay be hadto theaccompanying drawing, whichI shows diagrammatically the core andwindings of atransformer.

l is the core which may be constructed in the usual manner of laminae ofmagnetic material, and as shown in the drawing consists of three legswithl suitable end pieces connecting the legs. The primary winding 2surrounds a part of the central leg of the core, .and the .main portionof the secondary winding 3 surrounds another part of the same leg; thesewindings being shown as wound upon different parts of the core,I

so that there will be a large magnetic leak- `age between the twowindings. A second portion of Vthe secondary winding 4 is wound upon thesame pa'rtof the core as the primary winding and in1 close `proximitythereto, and this portion of lthe secondary winding is so connectedkthat` the electro-` motive force generated in it will be in oppositiont0 or will buck the electro-motiveforce 'generated in the mainp'ortionof the secondary winding. 'Ihe y'main portion of the secondary windingmay have taps 5, so that thel voltagesupplied to the load l may bevaried the well-knownl manner. If it is desired to obtain a large" rangeof voltages so that onlyl a small portion of this- .the opposing actionof winding 4 may become greater than desirable, and therefore thiswinding I have shown as provided with an intermediate tap 6, to whichthe. load may be connected.

It will, be Y understood that while for clearness I have illustrated thewindings as consistingof a -small number ofturns, and the secondary ashaving a small number'bf taps. conneotedthereto, that I do not limitmyself to .the Y particular arrangement shown. The primary winding maybe connectd by conductors 7 and. 8 to a suitable source of supply, whichis: not shown, and

the secondary winding may lee connected signed that the desiredsecondary voltage will be obtained, and taps 5 and 64 may also* bearranged to give suitable lesser voltages. It a short circuit occurswhen the secondary winding is connected so as to give either its whole,or a portion of. its whole voltage, greater leakage will occu'r betweenthe primary and the main portion of the secondary winding, and thisgreater leakage 01' itself would tend to cut down the short circuitcurrent in the secondary inthe well understood manner. The' opposingportion of the secondary dwill have a greater amount of'iux proportionalto the flux in the main portion flowing through it for a short circuitthan for normal load, and will, hence, have more effect in opposing themain voltage than for normal load and itsy action will therefore stillfurther decrease the secondary current. It will also tend to decreasethe primary flux. If the secondary winding is connected so that onlyaportion -of it be used, the short circuited current in this portionwill still'loe low, as the opposing portion 4L of the secn ondarywinding ywill have a proportionately greater effect upon this portion ofthe main winding than it does if the entire main winding is. used.

While I have shown my invention em- Vloodied in a particular form andarrangement of parts, l do not limit myself vto this form orarrangement, but seek in the appended claims to cover all'forms andarrangements which willvhe within the scope of my invention and will loeobvious -to those -skilled in the art.

vWhat I claim' as new and desire to secureby Letters Patent of theUnited States, is,-

l. ln an electricalapparatus, a core, an

mary winding inducing" windin g surrounding the coreand awinding ininductive relation thereto having a portion wound so that there will helarge magnetic leakage between it and the inducing winding, and a'second portion reversely connected to the irst portion and 1n closerproximity to the inducing winding' than the'said first portion.

2. ln an electrical transformer, a core, a primary winding surrounding.the core, and a secondary winding having a portion wound on 4adiii'erent part of the core, and a 'second portion reversely connectedto the thereof and upon the same part of the core;

asthe primary winding.

4. In an electrical transformer, a corea` primary winding surroundingthe core., andE a secondary winding having a portion pro vided. withtaps wound upon a dilterent: part of the core and second portion `reversely connected to the balance thereof. and

upon the same part of the core as thelpri'.-

5. In an electrical transformer, a core, a` primary winding su roundingthe core, andf a secondary winding having a portionwound upon adiiierent part ofthe core and provided with taps, and a second-portionreversely connected to the first portion, wound' upon the same part ofthe core vas the prie mary winding andprovidedwith taps. op lfnwitnesswhereof, l .have hereunto set my hand this 11thy day of Jaugust, 1909.

'svnnn n. aonannnsnn.

l/Vitnesses WnlLrs A. lsLiiLnR, Genuss l1. Lien.

